a. Field of the Invention
The invention relates generally to the field of medical instruments, and more particularly to a medical instrument for introduction into a body and having arbitrarily-shaped electrically conductive surfaces formed thereon, and methods of manufacturing such medical instruments.
b. Background Art
Catheters have been in use for medical procedures for many years. Among other uses, catheters can be used for medical procedures to examine, diagnose, and/or treat tissue while positioned at a specific location within the body otherwise inaccessible without more invasive procedures. For example, one procedure (often referred to as “catheter ablation”) utilizes a catheter to convey electrical energy to a selected location within the human heart to necrotize cardiac tissue. This procedure is often colloquially referred to as “ablation” of cardiac tissue.
Another procedure, oftentimes referred to as “mapping,” utilizes a catheter with sensing electrodes to monitor various forms of electrical activity in the human body. Various organs, including the heart and brain, may be mapped by a catheter having appropriate diagnostic functions. Mapping may be thought of as the opposite of ablation, in some respects. Specifically, a mapping catheter detects bioelectric impulses generated by the tissue in question and relays these bioelectric impulses to a diagnostic machine operably attached to the catheter. Accordingly, instead of transmitting energy to tissue, the mapping catheter transmits energy from tissue.
Regardless of the direction of energy transmission, present catheters generally mechanically mount the energy delivery media, such as electrodes, to the catheter surface. Further, the transmission media, typically one or more wires, is generally strung through an opening in the center of the catheter, and is not attached to the catheter save at the connection point with the energy delivery medium. Accordingly, as the catheter is steered, bent, or moved, stress may be applied to the internal wires. Additionally, when medical instruments are inserted into the catheter interior, the surgeon must exercise some degree of care to ensure the instruments do not interfere with the diagnostic functions of the catheter or, possibly, damage the wires.
Further, many diagnostic and energy delivery catheters have multiple wires running to a variety of diagnostic or energy delivery sites. At the catheter's proximal end, these wires often simply terminate with little or no identification separating one wire from the next, making attaching a wire to the appropriate connector pin of a medical device difficult.
Apparatus leads often suffer from similar problems. Leads may be used to deliver energy to tissue, typically in order to regulate tissue contraction through timed pulses of electricity. Such regulation may occur, for example, by a pacemaker. Further, in many neurosurgical applications, leads or catheters may be used to map an area of the brain by electrical measurement, as described above, or by electrically stimulating a portion of the brain to elicit a response. Energy may be further delivered through a lead to ablate tissue and alleviate irregular symptoms plaguing the tissue. In any of these energy-delivery applications, however, the problems identified above typically still exist.
Accordingly, there is a need for an improved medical device capable of transmitting electrical energy across its length either to or from a target site.